基于微卫星DNA标记分析刺槐叶瘿蚊遗传多样性指数与样本量的相关性

目的]探讨基于微卫星标记分析刺槐叶瘿蚊遗传多样性指数与样本量的相关关系。方法]设置了12个样本量梯度,选取11对微卫星引物分析了我国刺槐叶瘿蚊5个种群的遗传多样性指数。结果]表明,样本量的大小与平均等位基因数(Na)呈显著正相关,与有效等位基因数(Ne)呈中度正相关,与观测杂合度(Ho)呈负相关,而与期望杂合度(He)、Nei’s遗传多样性指数(H)和多态信息含量(PIC)没有明显相关性。此外,当样本量小于25时,随着样本量的增加,有效等位基因数增幅明显,观测杂合度起伏变化较大,但当样本量大于30时,随着样本量的增加,上述两个指数增(降)幅度平缓。结论]在利用微卫星DNA标记对我国刺槐叶瘿蚊种群的遗传多样性研究中,选取的最适样本量应为25～30,分析的最适遗传多样性指数应为期望杂合度、Nei’s遗传多样性指数和多态信息含量。该研究结果将为我们后续研究提供科学数据,并有助于分析其他入侵昆虫种群遗传结构的研究,同时可为其他双翅目昆虫的遗传多样性研究提供样本量参考。

Correlation Between Sample Size and Obolodiplosis robiniae Genetic Diversity Index Based on Microsatellite DNA Data

Objective] To obtain proper sample size for determining the genetic structure of a population of black locust gall midge Obolodiplosis robiniae (Haldemann) (Diptera, Cecidomyiidae).Method] The sample sizes with 12 gradients and 11 polymorphic microsatellite loci were used to assess five O. robiniae populations.Result] The results revealed that the sample size took significantly positive correlation with the number of alleles per locus (Na), and moderately positive correlation with the effective number of alleles per locus (Ne), but had moderately negative correlation with observed heterozygosity, however little influence was found on the expected heterozygosity, Nei''s genetic diversity and polymorphism information content. When the sample size<25, the number of alleles per locus increased rapidly and observed heterozygosity greatly changed, but they changed gently when the sample size>30.Conclusion] Concerning the genetic diversity analysis for populations of O. robiniae with microsatellite DNA markers, the optimum sample size appears to be 25~30, and the optimum parameters are the expected heterozygosity, Nei''s genetic diversity and polymorphism information content. The results of this study are helpful to microsatellite marker-based analyses of the genetic structure of populations of other invasive dipteran pests.